1. Field of the Invention
This invention relates to chairs, accessories for chairs, and to methods for supporting the lower back of a seated person.
2. Description of the Related Art
Conventional chairs do not provide adequate support of the lower back of a person sitting in the front portion of a chair and leaning backwards. In such sitting position, the lower back falls into a void created between the backrest and the seat of the chair, is suspended in the air, and hence unsupported.
To solve this problem, many methods have been devised. One of these methods is to provide a lumbar support cushion separately, or attached to the backrest of the chair at an appropriate height. The lumbar support cushion can be moved up and down along the backrest, but generally cannot be moved horizontally forwards and backwards according to the position of the lower back of a seated person. Moreover, when a person sits up or bends forward slightly, the lower back is unsupported.
Another method is to provide an S-shaped backrest and to utilize the protrusion thereon to support the lower back of a seated person. However, the position of the protrusion is generally fixed and thus cannot be adjusted according to the position of the lower back of the seated person. Therefore, an S-shaped backrest cannot satisfy the requirement for variable sitting positions and variable strengths necessary to support the lower back in different persons. Furthermore, conventional chairs and methods do not provide relief to persons with lumbar pain or soreness.
Accordingly, much opportunity for improvement remains in the area of providing support to the lower back of a seated person.